In the field of substrate-guided optical image relays, reflective, holographic or diffractive elements may cooperate with the surfaces of a relatively thin substrate to guide image rays along the substrate to produce a viewing region. This may be used for example to couple an image produced by a scanning projector or collimated light from a flat panel display to the eye of a viewer in a near-to-eye display and/or to provide a thin form-factor such as a flat panel display.